Use of antioxidant could ameliorate the negative impact of etoposide on human sperm DNA during chemotherapy.

RESEARCH QUESTION: A previous study showed that N-acetylcysteine (NAC), used after in-vitro exposure to the gonadotoxic chemotherapeutic drug etoposide, has the ability to decrease DNA damage in human spermatozoa; however, it showed no benefit when used before exposure. This study aimed to evaluate the impact of the NAC on the preservation of sperm quality during in-vitro exposure to etoposide. DESIGN: Twenty semen samples were submitted to four experimental conditions: control, NAC-only incubation, etoposide-only incubation, and concomitant etoposide and NAC incubation. After in-vitro incubation, semen parameters, sperm chromatin condensation, sperm DNA fragmentation, sperm oxidative stress and sperm metabolism were used to evaluate the role of NAC in protecting human spermatozoa from etoposide. RESULTS: Etoposide did not affect semen parameters, nor did it cause sperm oxidative damage or alterations in glycolytic profile. However, it induced chromatin decondensation and DNA fragmentation, which were fully prevented by NAC. CONCLUSIONS: NAC was able to protect sperm DNA integrity during etoposide treatment in vitro, suggesting that NAC may be useful as an adjuvant agent in preserving male fertility during chemotherapy treatments.

Protective role of N-acetylcysteine (NAC) on human sperm exposed to etoposide.

BACKGROUND: Although recent progress in cancer treatment has increased patient survival and improved quality of life, reproductive side effects are still for concern. One way to decrease gonadal impairment is to use cytoprotectors. In testicular cancer, etoposide is generally used in combination with other agents, but there are no in-vitro studies of sperm exposure to etoposide and cytoprotectors, namely N-acetylcysteine (NAC). METHODS: Twenty semen samples were individually divided into five groups: control, incubation with NAC alone, incubation with etoposide alone, sequential exposure of NAC followed by etoposide (pre-treatment) and sequential exposure of etoposide followed by NAC (post-treatment). Sperm characteristics, chromatin condensation (aniline blue), DNA fragmentation (TUNEL), oxidative stress (OxyDNA labelling) and glutathione quantification were used to evaluate the capabilities of NAC as a prophylactic (pre-treatment) or ameliorator (post-treatment) agent over the effects caused in sperm during in-vitro exposure to etoposide. RESULTS: No deleterious effects were observed on sperm motility or sperm membrane integrity. Results revealed that prophylactic use of NAC (pre-treatment) increased rates of immature sperm chromatin as compared to ameliorator use of NAC (post-treatment), and increased rates of sperm DNA fragmentation in relation to controls. Pre and post-treatment with NAC increased oxidative levels in comparison to controls, but also increased levels of cellular antioxidant glutathione. CONCLUSIONS: The results indicate that NAC has the ability to counteract etoposide-induced toxicity rather than preventing the etoposide cytotoxic effects over sperm DNA, suggesting that the administration of NAC to cells formerly exposed to etoposide is preferable to its prophylactic use. As the results evidenced that NAC seems to be more efficient in attenuating sperm etoposide cytotoxic effects instead of being used as a chemoprophylactic agent, this reinforces the idea that there might be a new NAC mechanism over DNA.

CONTEXTE: Bien que les récents progrès dans le traitement des cancers aient augmenté la survie des patients et amélioré leur qualité de vie, les effets secondaires sur la reproduction restent encore des motifs d'inquiétude. Une façon de réduire les altérations gonadiques consiste en l'utilisation de cytoprotecteurs. Dans le cancer du testicule, l'étoposide est habituellement utilisée en association avec d'autres agents, mais il n'existe aucune étude in vitro de l'exposition des spermatozoïdes à l'étoposide et à des cytoprotecteurs, notamment la N-acétylcystéine (NAC). MATÉRIEL ET MÉTHODES: Vingt échantillons de sperme ont été répartis en cinq groupes : témoins, incubés avec NAC seule, incubés avec étoposide seul, exposés séquentiellement à NAC puis à étoposide (pré traitement), et exposés séquentiellement à étoposide puis à NAC (post traitement). Les paramètres spermatiques, la condensation de la chromatine (bleu d'aniline), la fragmentation de l'ADN (TUNEL), le stress oxydatif (marquage OxyDNA) et la quantification du glutathion ont été utilisés pour évaluer les capacités de NAC comme agent prophylactique (pré traitement) ou comme améliorateur (post traitement) des effets causés sur les spermatozoïdes lors d'une exposition in vitro à l'étoposide. RÉSULTATS: Aucun effet délétère n'a été observé sur la mobilité ou sur l'intégrité de la membrane des spermatozoïdes. Les résultats montrent que l'utilisation prophylactique (pré traitement) de NAC augmente les taux des spermatozoïdes avec chromatine immature en comparaison de l'utilisation amélioratrice (post traitement) de NAC, et augmente les taux de fragmentation de l'ADN des spermatozoïdes par rapport aux témoins. L'utilisation de NAC en pré et post traitement augmente les taux d'oxydation par rapport aux témoins, mais augmente aussi les taux de glutathion anti-oxydant cellulaire. CONCLUSIONS: Les résultats indiquent que NAC possède la capacité de contrebalancer la toxicité induite par l'étoposide plutôt que celle d'empêcher les effets cytotoxiques de l'étoposide sur l'ADN des spermatozoïdes ; ceci suggère que l'administration de NAC aux cellules préalablement exposées à l'étoposide est préférable à son utilisation prophylactique. Comme les résultats témoignent que NAC semble être plus efficace à atténuer les effets cytotoxiques de l'étoposide sur les spermatozoïdes plutôt que d'être utilisée comme agent chimio prophylactique, ceci renforce l'idée qu'il pourrait exister un nouveau mécanisme de NAC sur l'ADN. MOTS-CLÉS: N-acétylcystéine (NAC), Etoposide, Fragmentation de l'ADN spermatique, Stress oxydatif spermatique.

Impact of Metformin on Male Reproduction.

Male infertility has been increasing over the last decades being nowadays a pressing health problem. Diabetes mellitus (DM) can contribute directly or indirectly to male infertility due to an abnormal spermatogenesis, which results in a decreased sperm quality. Type 2 Diabetes mellitus (T2DM) is responsible for the vast majority of DM cases, being frequently treated with oral antidiabetic drugs. Metformin is the most cost-effective therapy for the treatment of T2DM. This biguanide is an oral insulin-sensitizing agent capable of increasing insulin sensitivity and decreasing plasma fasting insulin levels. The main metabolic action of this drug occurs in the liver. However, it has been shown that metformin acts on a variety of organs including the male reproductive system. With the rising numbers of diabetic individuals among younger populations, there is an increase in the consumption of metformin in individuals of this age group. As a result, it is important to discuss the role of metformin in male fertility. This review presents the most recent data available from studies on the effects of metformin on male reproductive system. Together with the discussion of these effects, their significance to male fertility is also debated.